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Subject[PATCH v1 5/5] ASoC: tegra: ahub: Reset hardware properly
Date
Assert hardware reset before clocks are enabled and then de-assert it
after clocks are enabled. This brings hardware into a predictable state
and removes relying on implicit de-assertion of resets which is done by
the clk driver.

Tested-by: Peter Geis <pgwipeout@gmail.com>
Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
sound/soc/tegra/tegra30_ahub.c | 33 ++++++++++++++++-----------------
sound/soc/tegra/tegra30_ahub.h | 1 +
2 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/sound/soc/tegra/tegra30_ahub.c b/sound/soc/tegra/tegra30_ahub.c
index 4dbb58f7ea36..246cf6a373a1 100644
--- a/sound/soc/tegra/tegra30_ahub.c
+++ b/sound/soc/tegra/tegra30_ahub.c
@@ -65,10 +65,20 @@ static int tegra30_ahub_runtime_resume(struct device *dev)
{
int ret;

+ ret = reset_control_assert(ahub->reset);
+ if (ret)
+ return ret;
+
ret = clk_bulk_prepare_enable(ahub->nclocks, ahub->clocks);
if (ret)
return ret;

+ ret = reset_control_reset(ahub->reset);
+ if (ret) {
+ clk_bulk_disable_unprepare(ahub->nclocks, ahub->clocks);
+ return ret;
+ }
+
regcache_cache_only(ahub->regmap_apbif, false);
regcache_cache_only(ahub->regmap_ahub, false);

@@ -462,7 +472,6 @@ static int tegra30_ahub_probe(struct platform_device *pdev)
{
const struct of_device_id *match;
const struct tegra30_ahub_soc_data *soc_data;
- struct reset_control *rst;
struct resource *res0;
void __iomem *regs_apbif, *regs_ahub;
int ret = 0;
@@ -475,22 +484,6 @@ static int tegra30_ahub_probe(struct platform_device *pdev)
return -EINVAL;
soc_data = match->data;

- /*
- * The AHUB hosts a register bus: the "configlink". For this to
- * operate correctly, all devices on this bus must be out of reset.
- * Ensure that here.
- */
- rst = of_reset_control_array_get_exclusive(pdev->dev.of_node);
- if (IS_ERR(rst)) {
- dev_err(&pdev->dev, "Can't get reset: %p\n", rst);
- return PTR_ERR(rst);
- }
-
- ret = reset_control_deassert(rst);
- reset_control_put(rst);
- if (ret)
- return ret;
-
ahub = devm_kzalloc(&pdev->dev, sizeof(struct tegra30_ahub),
GFP_KERNEL);
if (!ahub)
@@ -507,6 +500,12 @@ static int tegra30_ahub_probe(struct platform_device *pdev)
if (ret)
return ret;

+ ahub->reset = devm_reset_control_array_get_exclusive(&pdev->dev);
+ if (IS_ERR(ahub->reset)) {
+ dev_err(&pdev->dev, "Can't get reset: %p\n", ahub->reset);
+ return PTR_ERR(ahub->reset);
+ }
+
res0 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
regs_apbif = devm_ioremap_resource(&pdev->dev, res0);
if (IS_ERR(regs_apbif))
diff --git a/sound/soc/tegra/tegra30_ahub.h b/sound/soc/tegra/tegra30_ahub.h
index 063aed5037d7..ceb056575e98 100644
--- a/sound/soc/tegra/tegra30_ahub.h
+++ b/sound/soc/tegra/tegra30_ahub.h
@@ -510,6 +510,7 @@ struct tegra30_ahub_soc_data {
struct tegra30_ahub {
const struct tegra30_ahub_soc_data *soc_data;
struct device *dev;
+ struct reset_control *reset;
struct clk_bulk_data clocks[2];
unsigned int nclocks;
resource_size_t apbif_addr;
--
2.29.2
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